28. Ilazki `moon', which as we have already said
corresponds to eguzki
`sun', seems to us to be a composition of ila-uzki. The
reduction of
the diphthong au is a current thing as much in Basque
as in the
Indo-European languages.

Au contracts in o, in a and in u.
As an example of the first, we have
in Bizkaian the verbal forms dot of daut,
nozu of nauzu. Uhlenbeck very
prudently says that this contraction is limited to the cases
in which
the diphthong is followed by a consonant, and as a result
there are verbal
forms which conserve it, such as dau, dabe
(from *daue), nau, nabe
( *naue).

Au reduces to u in very rare cases, e.g. the
suletine urthiki, from
aurthiki `arrojar'. As Uhlenbeck says, together with
basaurde `jabali'
we also have in Gipuzkoan basurde, which comes from
the first, or in another case,
is a composition of bas (= basa) and
urde.

On the other hand, the contraction of au to a is
frequent in all
dialects. (Uhlenbeck, Gavel). There remains in some cases
the doubt
whether the phonetic process is the reverse, by dipthongation
sporadic
of a to au before n. This phenomenon is
present in the Bizkaian
dialect. Uhlenbeck cites, among other various examples,
aundi `large',
de andi. On the contrary, Gavel believes that
andi comes from aundi and
that the accumulation of consonants has served to facilitate
the elision
of the u. This could also be the case for ilauzki.

Certain au diphthongs have become ai in
suletino, where, for example,
laudatu (from the Latin laudatum) has converted
to laidatU. It is also
common of the suletino the reduction aun to añ
by interim of ain.
(Gavel).

The contraction of au to a in all Basque dialects
being very frequent,
the examples that we could cite are very numerous. Beside
auspo
`fuelle', aulki `chair, bench', aurpegi `face',
jaube `owner', Jaungoiko
`God', aurkitu `to find', laurogei `eighty',
laureun `four hundred', and
the verbal forms dauku, zauku, etc., exist as many
other forms aspo,
alki, arpegi, etc.

29. All of this allows one to suppose that ilazki
proceeds from
*ilauzki. If one wants to object that basaurde
conserves the diphthong or
reduces to basurde, we can answer that `forest' in
Euskara, is not basa
but baso. The first of these two forms intervenes in
compound words and
means `wild'. Baso also enters in some compounds
with identical
meaning. Basauri `locality of the forest' and noun
of place, conserves
the diphthong. But in basurde we must see more
correctly a compound of
baso-urde or bas-urde.

Apart from the fact that the reduction of au to u
is very infrequent, in
the concrete case of *ilauzki we would have had
*iluzki, and so the name
of the moon would be confused with that of the sun, since, as
we have
seen, iluzki is one of the variants of eguzki.

30. Even more than the phonetic demonstrations, it is
important to
consider the reasons of semantic order. Our opinion is that
eguzki is
formed once weakened egu `sun', with the end of
designating
concretely the celestial body of the day. Por aquel entonces,
uzki
would be current name of `eye'. Eguzki, then,
properly means `eye
(of the) sun, eye of the day', in the same way that ilazki
means `eye
(of the) moon, eye of the night'.